Fig. 5

Deregulation of the FGF/FGFR system in MM. A Aberrant activation of the FGFR signaling can occur in MM as the consequence of genomic alterations affecting FGFR3 gene, including t(4;14) chromosomal translocation, point mutations in the sequences codifying for the TK domain, or FGFR3 gene amplification. B Aberrant activation of the FGFR signaling can also be due to increased production of FGF ligands by both MM and BMS cells. MM and BMS cells produce several members of the FGF family that stimulate MM cell proliferation and survival. FGF2 produced by MM cell can also stimulate BM angiogenesis and the secretion of IL-6 by BMSCs that in turn stimulate MM cell proliferation and FGF2 production